The new Electronic System for Travel Authorization (ESTA) is now active.  If you live in a visa waiver country, and intend to visit the USA without a visa, you no longer need to fill out a I-94 form on the airplane.  You can go online to the US Homeland Security webpage and obtain your entry authorization before you depart. 

For now, this convenient method is optional.  On January 1, 2009, it will be mandatory to obtain your entry authorization on line at least three days before you depart.  Once you obtain an authorization, it will be valid for two years.

Here is a link to the ESTA webpage.